Heretofore, a pressure sensor stated in JP-A-2000-275128 has been proposed as the pressure sensor of the type specified above. The pressure sensor includes a package in which a metallic housing having a pressure introducing port is joined unitarily with a resinous connector case having a terminal pin for exchanging signals with the exterior.
The package includes a detection portion which generates electric signals corresponding to a pressure introduced from the pressure introducing port. The detection portion is configured including strain gauges which are formed by doping a semiconductor chip with, for example, a P-type impurity. Besides, the detection portion is joined through a glass paste (low-melting glass) on the front surface of a metallic diaphragm which is constructed by thinning part of a metallic stem.
With the pressure sensor configured as stated in JP-A-2000-275128, in order to join the semiconductor chip onto the metallic diaphragm, a mounting area corresponding to the size of the semiconductor chip must be secured on the upper surface of the diaphragm. Since the strain gauges numbering four are fabricated in one semiconductor chip, the size of the semiconductor chip is large, and also the mounting area which must be secured for the semiconductor chip becomes large. Therefore, the versatility of a place where the semiconductor chip is joined is low, and it is desired to reduce the size of the semiconductor chip. Thus, it is required for a pressure sensor to reduce the size of the semiconductor chip constructing a strain gauge.